This is a new device for attaching to manual dosing devices for use in vertebroplasty, comprising a body (1) fitted with a coupling or connector (2) for connecting it to a manual dosing device, and two or more delivery tubes (3), each with an applicator needle, wherein said body (1) comprises a connection chamber (1.1) placing said connector (2) and said tubes (3) in communication via said body (1), and wherein a diverter or conveyor element (4), with passages (4.1), contained inside said chamber (1.1) in said body (1), and controllable from the outside of said body (1), places said connector (2) in communication with one or more of the delivery tubes (3), depending on the position in which said element is placed. The passages (4.1) through the diverter or conveyor element (4) are all in communication with one another.